Substituted sulfilimine compounds are useful intermediates in the preparation of sulfoximine compounds, which have insecticidal activity. Cyano-substituted sulfilimine compounds have been prepared by reaction of a corresponding sulfide compound with cyanamide in the presence of iodobenzene diacetate. However, iodobenzene diacetate is expensive and causes waste disposal problems.
Substituted sulfilimine compounds have also been prepared by replacing the iodobenzene diacetate with hypochlorite. A corresponding sulfide compound is reacted with cyanamide in the presence of the hypochlorite. However, a corresponding sulfoxide compound is also produced as one of the reaction by-products. The yield of the substituted sulfilimine compound is affected by the amount of reaction by-products produced. For instance, 5-[1-(methylthio)ethyl]-2-trifluoromethylpyridine (the sulfide compound) is oxidized to N-cyano-S-methyl-S-[1-(6-trifluoromethyl-3-pyridinyl)ethyl]sulfilimine (the sulfilimine compound) in the presence of sodium hypochlorite and cyanamide. A by-product of the oxidation reaction is 5-[1-(methylsulfinyl)ethyl]-2-trifluoromethylpyridine (the sulfoxide compound), which may be produced at 10% or greater. It would be desirable to have a process for producing the sulfilimine compound at higher yields, such as by decreasing the amount of sulfoxide compound produced.